In Otto-type gas engines, fuel and combustion air are premixed upstream of the cylinders of the engine using a venturi mixer or another mixing and injection device. In order to maximize the fuel/air mixture homogeneity and to allow a low pressure fuel supply, the fuel is often injected upstream of the compressor. Such mixing and injection concepts result in relatively large volumes of ignitable mixture outside of the combustion chamber and do not allow the control of the fuel injection timing to avoid flashback. Both controlled injection and small ignitable mixture volumes upstream of the cylinder are especially important for fuels with high flashback risk such as hydrogen. Port injection techniques are used to provide appropriate timing of fuel injection to avoid flashback, but at a cost of reducing the mixing quality. The reduced mixing quality may lead to increased emissions, reduced power and a restricted operating range of the engine. Accordingly, it is desired to improve mixing and injection of fuels for internal combustion engines to achieve high power density, efficient operation, and reduced emissions.